Problem: Khan.scratchpad.disable(); To move up to the maestro level in her piano school, Emily needs to master at least $115$ songs. Emily has already mastered $36$ songs. If Emily can master $9$ songs per month, what is the minimum number of months it will take her to move to the maestro level?
Explanation: To solve this, let's set up an expression to show how many songs Emily will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Emily Needs to have at least $115$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 115$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 115$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 9 + 36 \geq 115$ $ x \cdot 9 \geq 115 - 36 $ $ x \cdot 9 \geq 79 $ $x \geq \dfrac{79}{9} \approx 8.78$ Since we only care about whole months that Emily has spent working, we round $8.78$ up to $9$ Emily must work for at least 9 months.